CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total Stockholders' Equity	Common Stock	Additional Paid-In Capital	Cumulative Dividends In Excess Of Earnings	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Total
Balance at Dec. 31, 2014	$ 10,735,297	$ 459,746	$ 11,431,987	$ (1,132,541)	$ (23,895)	$ 261,802	$ 10,997,099
Balance (in shares) at Dec. 31, 2014		459,746
Increase (Decrease) in Stockholders' Equity
Net income	39,633			39,633		8,566	48,199
Other comprehensive income	(8,555)				(8,555)		(8,555)
Issuance of common stock, net	144,645	$ 4,054	140,591			(2,659)	141,986
Issuance of common stock, net (in shares)		4,054
Conversion of DownREIT units (in shares)		75
Repurchase of common stock	(8,006)	$ (178)	(7,828)				(8,006)
Repurchase of common stock (in shares)		(178)
Exercise of stock options	27,511	$ 820	26,691				27,511
Exercise of stock options (in shares)		820
Amortization of deferred compensation	21,068		21,068				21,068
Common dividends	(783,578)			(783,578)			(783,578)
Distributions to noncontrolling interests	(263)		(263)			(13,444)	(13,707)
Issuance of noncontrolling interests						38,440	38,440
Balance at Sep. 30, 2015	10,167,752	$ 464,442	11,612,246	(1,876,486)	(32,450)	292,705	10,460,457
Balance (in shares) at Sep. 30, 2015		464,442
Balance at Dec. 31, 2015	9,343,643	$ 465,488	11,647,039	(2,738,414)	(30,470)	402,674	9,746,317
Balance (in shares) at Dec. 31, 2015		465,488
Increase (Decrease) in Stockholders' Equity
Net income	569,086			569,086		9,540	578,626
Other comprehensive income	306				306		306
Issuance of common stock, net	55,711	$ 2,290	53,421				55,711
Issuance of common stock, net (in shares)		2,290
Conversion of DownREIT units to common stock	6,093	$ 145	5,948			(6,093)
Conversion of DownREIT units (in shares)		145
Repurchase of common stock	(8,667)	$ (236)	(8,431)				(8,667)
Repurchase of common stock (in shares)		(236)
Exercise of stock options	3,473	$ 133	3,340				3,473
Exercise of stock options (in shares)		133
Amortization of deferred compensation	19,307		19,307				19,307
Common dividends	(806,243)			(806,243)			(806,243)
Distributions to noncontrolling interests	(36)		(36)			(18,651)	(18,687)
Issuance of noncontrolling interests						4,785	4,785
Deconsolidation of noncontrolling interests	439		(36)	475		67	506
Balance at Sep. 30, 2016	$ 9,183,112	$ 467,820	$ 11,720,552	$ (2,975,096)	$ (30,164)	$ 392,322	$ 9,575,434
Balance (in shares) at Sep. 30, 2016		467,820